CurtHagenlocher commented on code in PR #329:
URL: https://github.com/apache/arrow-dotnet/pull/329#discussion_r3141366187
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src/Apache.Arrow.Scalars/Variant/VariantValueWriter.cs:
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@@ -314,160 +411,232 @@ public void WriteDecimal16(SqlDecimal value)
lo = (long)uLo;
}
- ms.WriteByte(scale);
- WriteInt64LE(ms, lo);
- WriteInt64LE(ms, hi);
+ buf.Append(scale);
+ buf.WriteInt64LE(lo);
+ buf.WriteInt64LE(hi);
}
/// <summary>Writes a string. Uses the short-string encoding when the
UTF-8 byte length is ≤ 63.</summary>
public void WriteString(string value)
{
if (value == null) throw new ArgumentNullException(nameof(value));
- MemoryStream ms = BeforeWriteValue();
+ ref Buffer<byte> buf = ref BeforeWriteValue();
int byteCount = Encoding.UTF8.GetByteCount(value);
if (byteCount <= 63)
{
-
ms.WriteByte(VariantEncodingHelper.MakeShortStringHeader(byteCount));
+
buf.Append(VariantEncodingHelper.MakeShortStringHeader(byteCount));
}
else
{
-
ms.WriteByte(VariantEncodingHelper.MakePrimitiveHeader(VariantPrimitiveType.String));
- WriteInt32LE(ms, byteCount);
+
buf.Append(VariantEncodingHelper.MakePrimitiveHeader(VariantPrimitiveType.String));
+ buf.WriteInt32LE(byteCount);
}
- // Encode UTF-8 directly into the MemoryStream's buffer.
- int dataPos = (int)ms.Position;
- int needed = dataPos + byteCount;
- if (needed > ms.Length)
- {
- ms.SetLength(needed);
- }
- Encoding.UTF8.GetBytes(value, 0, value.Length, ms.GetBuffer(),
dataPos);
- ms.Position = needed;
+ // Encode UTF-8 directly into the buffer.
+ Span<byte> dest = buf.GetSpan(byteCount);
+#if NET8_0_OR_GREATER
+ Encoding.UTF8.GetBytes(value, dest);
+#else
+ Encoding.UTF8.GetBytes(value, 0, value.Length, buf.RawBuffer,
buf.Length);
+#endif
+ buf.Advance(byteCount);
}
/// <summary>Writes a binary blob.</summary>
- public void WriteBinary(byte[] data)
+ public void WriteBinary(ReadOnlySpan<byte> data)
{
- if (data == null) throw new ArgumentNullException(nameof(data));
- MemoryStream ms = BeforeWriteValue();
-
ms.WriteByte(VariantEncodingHelper.MakePrimitiveHeader(VariantPrimitiveType.Binary));
- WriteInt32LE(ms, data.Length);
- ms.Write(data, 0, data.Length);
+ ref Buffer<byte> buf = ref BeforeWriteValue();
+
buf.Append(VariantEncodingHelper.MakePrimitiveHeader(VariantPrimitiveType.Binary));
+ buf.WriteInt32LE(data.Length);
+ buf.Append(data);
}
/// <summary>Writes a UUID.</summary>
public void WriteUuid(Guid value)
{
- MemoryStream ms = BeforeWriteValue();
-
ms.WriteByte(VariantEncodingHelper.MakePrimitiveHeader(VariantPrimitiveType.Uuid));
+ ref Buffer<byte> buf = ref BeforeWriteValue();
+
buf.Append(VariantEncodingHelper.MakePrimitiveHeader(VariantPrimitiveType.Uuid));
+ Span<byte> raw = stackalloc byte[16];
#if NET8_0_OR_GREATER
- Span<byte> buf = stackalloc byte[16];
- value.TryWriteBytes(buf, bigEndian: true, out int _);
- ms.Write(buf);
+ value.TryWriteBytes(raw, bigEndian: true, out _);
#else
- byte[] native = value.ToByteArray();
// Convert from .NET mixed-endian to big-endian (RFC 4122).
- _scratch[0] = native[3]; _scratch[1] = native[2]; _scratch[2] =
native[1]; _scratch[3] = native[0];
- _scratch[4] = native[5]; _scratch[5] = native[4];
- _scratch[6] = native[7]; _scratch[7] = native[6];
- Buffer.BlockCopy(native, 8, _scratch, 8, 8);
- ms.Write(_scratch, 0, 16);
+ byte[] native = value.ToByteArray();
Review Comment:
Hmm... we have an unsafe helper for this somewhere
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